diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 4033e65ace7..ac4eea4a50b 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -218,6 +218,9 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   }
 }
 
+// Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h.
+DwarfDebug::~DwarfDebug() { }
+
 // Switch to the specified MCSection and emit an assembler
 // temporary label to it if SymbolStem is specified.
 static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index b5b07aee11d..d7359a3105e 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -557,6 +557,8 @@ public:
   //
   DwarfDebug(AsmPrinter *A, Module *M);
 
+  ~DwarfDebug() override;
+
   void insertDIE(const MDNode *TypeMD, DIE *Die) {
     MDTypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));
   }